Re: [PATCH] drm/panic: Fix the potential loop that causes kmsg to not display correctly

[Jocelyn Falempe]

On 26/01/2026 06:40, luyuantao01 wrote:
From: luyuantao <luyuan...@kylinos.cn>
When kmsg_buf completes drawing the screen and yoffset is less than 0,
kmsg_dump_get_buffer continues to obtain the buffer. This potential loop may
cause panic_flush not to be executed immediately or even not to be executed
at all, resulting in a garbled screen display instead of normal logs

So, the loop should be exited immediately after drawing kmsg_buf

You're right, the loop should stop when the screen is filled.

I would prefer writing it like this:

while (yoffset >= 0 && kmsg_dump_get_buffer(&iter, false, kmsg_buf, 
sizeof(kmsg_buf), &kmsg_len)) {

Can you send a v2 with this changed?

Best regards,

--

Jocelyn


Signed-off-by: luyuantao <luyuan...@kylinos.cn>
---
  drivers/gpu/drm/drm_panic.c | 3 +++
  1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
index d4b6ea42db0f..4b44011b4be1 100644
--- a/drivers/gpu/drm/drm_panic.c
+++ b/drivers/gpu/drm/drm_panic.c
@@ -592,6 +592,9 @@ static void draw_panic_static_kmsg(struct 
drm_scanout_buffer *sb)
                        end = start;
                        start--;
                }
+
+               if (yoffset < 0)
+                       break;
        }
  }